1. Field of the Invention
The present invention is in the field of accumulator devices and pertains more particularly to an accumulator device having a novel plug and locking assembly which may be readily positioned in the oil port of the accumulator to define an effective seal.
2. The Prior Art
As conducive to an understanding of the present invention, it is to be noted that pressure accumulators conventionally employ a plug assembly which may include a valve, the assembly being mounted in the oil port of a pressure vessel. From time to time it becomes necessary to remove and replace the plug assembly. If an attempt is made with conventional accumulator devices to release the mechanism which retains the plug assembly in position before all of the pressure has been relieved from the interior of the accumulator, the plug may suddenly blow out of the oil port, causing severe injury to the operator.
In U.S. Pat. No. 2,936,787 there is disclosed an accumulator mechanism employing a locking ring which prevents such blow outs. Briefly, the accumulator of the noted reference includes a plug having a retaining flange of smaller outside diameter than the oil port whereby the plug may be inserted into the interior of the pressure vessel. The locking ring is comprised of a series of arcuate metal segments which together form an annulus. The outside diameter of the segments is greater than the diameter of the oil port and the inside diameter of the segments is smaller than the diameter of the flange of the plug.
The segments are held together by a surrounding continuous elastomeric resilient ring, enabling the segments to be deformed from a coplanar alignment by folding the ring and, thus folded, to be passed into the interior of the pressure vessel through the oil port. Thereafter the shank of the plug is drawn outwardly through the aperture defined by the segments until the under surface of the flange seats against the upper surface of the segments, whereby the plug may not be removed or blown out through the oil port even after the clamping nut typically employed to maintain the plug in position has been removed by an operator.
With the prior art assembly described, after emplacement of the plug and locking ring, it has been necessary to force a seal member upwardly into the annular space defined between the oil port and the external diameter of the plug. Obviously, since the seal provides the major resistance to leakage of oil under pressure, tight and effective interfit between the annular seal and the opposed faces of the oil port and plug must be secured. However, since the sealing ring which is to provide the seal must perforce engage intimately both of the noted surfaces, positioning thereof is a tedious job and often requires the use of tools, which must be pushed against the under surface of the ring to advance the same upwardly to the desired location within the oil port. If the ring or the adjacent faces of the plug or oil port are scarred in the course of positioning, there is provided a path for oil leakage. Additionally, in the noted device, in order to develop an adequate seal it is necessary that the ring be compressed or clamped subsequent to positioning between washers to develop lateral expansion.
Although O-rings are conventionally effectively empolyed by seating the same within a ring or groove in one of the members to be sealed, the use of a pre-mounted O-ring in such retaining groove in accumulator devices of the type disclosed in the above referenced United States patent which use a continuous locking ring has heretofore been impossible since the outer diameter of the O-ring must, of necessity, be larger than the inner diameter of the segments, to provide a sealing engagement with the face of the oil port, thus precluding passage of the O-ring through the smaller diameter opening defined by the segments of the locking ring.
Thus, blow out resistant locking ring assemblies heretofore have required the use of an upwardly mounted gasket member, despite the drawbacks hereinabove itemized.